CULPEPER, VA. - There once was a time when Ray Tolson thought the sport of "Punkin Chunkin" sounded as crazy as can be, when the notion of spending as much as $200,000 to build a 100-foot-long "gun" designed to fire a pumpkin nearly a mile seemed silly. But that was another Ray Tolson, a Ray Tolson who didn't study air pressure and cloud speed in search of the ideal "air shelf" where an 8- to 10-pound pumpkin could sail perfectly. Who didn't commission university horticulturists to breed pumpkins that are precisely 9.5 inches in diameter, round and with a thick skin &#8212; the perfect projectile.

With the World Championship Punkin Chunkin and a chance to best his world record of 4,434.28 feet less than three weeks away, Tolson, 61, was in his yard Friday, furiously fiddling with the gun. He said he spent 5,000 hours building it.

"I haven't had time to mow," said Tolson, who calls himself a high-tech redneck. "The point is to use the maximum G4 force on the pumpkin without destroying it," he said.

Tolson's fanaticism is hardly unusual in a sport that went from a casual fall contest 20 years ago among friends to a $25-a-head event that draws 40,000 people and corporate sponsorship. This year, all machines are required to comply with American Society of Mechanical Engineers standards. One hundred teams will compete in the Nov. 4-6 contest in Millsboro, Del.

Punkin Chunkin is essentially a service organization. Everyone who helps put on the event is a volunteer, and all the profit goes to college scholarships and to St. Jude Children's Research Hospital in Memphis, Tenn. The event gives away about $80,000 each year.

Though Tolson will talk generally about the skills involved in becoming a world champion, there is a limit to how much he will say.

He won't say the precise pressure in his air cannon nor the gourd's velocity. The secret is a cocktail of air and pressure.